Montes helped found Digilant in 2009, back when it was still called Adnetik and operated as the trading desk unit of French agency conglomerate Havas.

Later, when Adnetik was spun off in a management-led buyout, he continued to run the company as CEO. It would later rebrand to downplay its former Havas affiliation and increase its appeal to would-be agency customers concerned about exposing their client data to Havas agency teams.

Digilant has not yet named a successor, according to a rep, though co-founder and Chief Operating Officer Nathan Woodman is certainly high on the list.

Speaking with AdExchanger, DataXu CEO Mike Baker said the hire helps the company position for global expansion and serve multinational clients that want to execute cross-border marketing strategies.

It also doesn't hurt that Montes speaks fluent "agency" from his years as managing director for Havas Digital, North America.

"We're outsiders to the traditional agency business," Baker said, invoking the company's roots as a Boston-based technology company with connections to MIT. "The word 'media' is not in our name. Sometimes it's hard for us to communicate as effectively as those who have done that through [their] career."